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Merrimack River

Merrimack River Current Water Temperature and Forecast

On this page, you will find comprehensive information about the water temperature in Merrimack River, including current readings, historical data and trends, monthly averages, as well as weather forecasts and upcoming temperature predictions. We find every spot where you can swim and tell you what the water temperature is there today and throughout the year.

Current Water Temperature in Merrimack River

15.9°C

TODAY

16.1°C

YESTERDAY

13.8°C

A WEEK AGO

As of today, the minimum water temperature in the Merrimack River ranges from 60°F (15°C) to 65°F (18°C). The water is comfortable for most people, making it an ideal range for water sports enthusiasts. The temperature does not cause significant discomfort, and swimming will be pleasant for the majority. However, it's important to remember that prolonged exposure to the water can still lead to cooling, so it's essential to monitor the time spent in the water, especially for children or elderly people.

It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.

Analysis, Historical Data, and Forecast of Water Temperature

Water Temperature Chart for Merrimack River Over the Last 30 Days

Today the water temperature in Merrimack River is lower than the same day in previous years. The water temperature range here in June is from 14°C to 22°C. The water temperature is trending upward, and it has increased both over the past 30 days and the past week.

The forecasted water temperature values for Merrimack River are presented in the table below.

The actual water temperature values near the shore may differ by a few degrees from the stated values. For the development of the forecast, we use our own mathematical model that takes into account the current water temperature changes, historical data, and key weather trends, including wind strength and direction, and air temperature in each specific region.

Daily Water Temperature Chart

DateCurrentAverageForecast
May 2813.8°C13.4°C
May 2913.9°C13.4°C
May 3014.2°C13.4°C
May 3117.0°C13.4°C
Jun 117.4°C18.5°C
Jun 215.8°C18.5°C
Jun 316.1°C18.5°C
Jun 415.9°C18.5°C
Jun 518.5°C16.1°C
Jun 618.5°C16.3°C
Jun 718.5°C16.4°C
Jun 818.5°C16.5°C
Jun 918.5°C16.6°C
Jun 1018.5°C16.7°C
Jun 1118.5°C16.8°C
Jun 1218.5°C16.9°C
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast

Water Temperature Ranges in Merrimack River by Month

January

MinimumAverageMaximum
0°C4.5°C9°C

February

MinimumAverageMaximum
0°C4.5°C9°C

March

MinimumAverageMaximum
0°C5.5°C11°C

April

MinimumAverageMaximum
3°C9.5°C16°C

May

MinimumAverageMaximum
8°C13.4°C21°C

June

MinimumAverageMaximum
14°C18.5°C22°C

July

MinimumAverageMaximum
17°C20°C24°C

August

MinimumAverageMaximum
17°C21.4°C23°C

September

MinimumAverageMaximum
11°C17.6°C19°C

October

MinimumAverageMaximum
8°C13.3°C16°C

November

MinimumAverageMaximum
3°C8.1°C16°C

December

MinimumAverageMaximum
3°C4.7°C8°C

Monthly Water Temperature Histogram for Merrimack River

Water Temperature in Cities and Towns on Merrimack River

United States (New Hampshire)
15.3°C
United States (New Hampshire)
15.6°C
United States (New Hampshire)
15.5°C
United States (Massachusetts)
16.4°C
United States (Massachusetts)
18.7°C
United States (Massachusetts)
18.8°C
Newburyport
United States (Massachusetts)
19.2°C

Merrimack River Weather

JUNE 5

17°C / 29°C
slight rain showers

rain: 21% | wind: 9 km/h

JUNE 6

17°C / 29°C
slight rain showers

rain: 38% | wind: 15 km/h

JUNE 7

17°C / 28°C
light drizzle

rain: 38% | wind: 15 km/h

Water Temperature in Merrimack River: General Trends and Swimming Opportunities

Source Pemigewasset River-Winnipesaukee River juncture
• location: Franklin, Merrimack County, New Hampshire
Mouth Gulf of Maine
• location Newburyport, Essex County, Massachusetts
Length 117 mi (188 km)

The Merrimack River, which flows through New Hampshire and Massachusetts, is one of the largest rivers in the northeastern United States. The water temperature in the Merrimack River varies throughout the year, with cooler temperatures in the spring and fall, often ranging from 40°F to 55°F (4°C to 13°C). In the summer months, the water warms up to more comfortable temperatures, typically ranging between 60°F and 75°F (15°C to 24°C), making it more suitable for swimming.

Swimming in the Merrimack River is possible, particularly in areas with slower-moving water or designated recreational zones. Some parts of the river, especially around cities like Lowell and Lawrence, offer public access points where people can swim or relax by the water. However, caution is recommended, as the river's current can be strong in certain sections, and water quality can fluctuate, especially after heavy rainfall. While swimming isn't the most common activity in the Merrimack, it remains an option for those looking to cool off during the summer months. The river is also popular for boating, fishing, and kayaking, attracting a wide range of water enthusiasts.

Geographical Location of Merrimack River

Frequently Asked Questions About Merrimack River and its Water Temperatures

What is the current water temperature in Merrimack River?

The water temperature today in Merrimack River ranges from 60°F (15.3°C) to 67°F (19.2°C).

What is the water temperature in Merrimack River during the summer months?

The average water temperature in Merrimack River during the summer months is typically between 65°F to 71°F (19°C to 21°C), and it can reach up to 75°F (24°C) at its warmest. However, in some years, the temperature may exceed this range.

What is the water temperature in Merrimack River in May?

The average water temperature in Merrimack River in May ranges from 46°F to 70°F (8°C to 21°C).

What is the water temperature in Merrimack River in September?

The average water temperature in Merrimack River in September is typically between 52°F to 66°F (11°C to 19°C).

Where does Merrimack River flow?

Merrimack River flows through United States (New Hampshire, Massachusetts).

Is it possible to swim in the Merrimack River?

Yes, it is possible to swim in the Merrimack River. However, safety and current conditions should always be checked prior to swimming due to occasional pollution issues.

What major cities are located on Merrimack River?

Cities along the course of Merrimack River include Concord (New Hampshire), Haverhill (Massachusetts), Lawrence (Massachusetts), Lowell (Massachusetts), Manchester (New Hampshire), Nashua (New Hampshire).